Sealing means between master cylinder and brake booster

ABSTRACT

A sealing member for preventing liquid entrance into the master cylinder housing from the clearance of the connecting portion between the master cylinder housing and the brake booster housing, said sealing member being formed in a tubular shape and fitted on a sleeve of the master cylinder housing, comprising an axial projection normally making contact with the booster housing, and an air compensating slot.

United States Patent Watabe et a].

[ 1 July 25,1972

[54] SEALING MEANS BETWEEN MASTER CYLINDER AND BRAKE BOOSTER [72]inventors: Shlgeru Watabe, Kariya; Atsushi Ohmi,

Nagoya, both of Japan [73] Asaignee: Alain Selkl Kabushlkl Kalaha,Kariya Aichi Pref., Japan [22] Filed: Oct. 23, 1970 [21] Appl. No.:83,535

[30] Foreign Application Priority Data Oct. 24, 1969 Japan ..44/10l53152 us. C1 .L ..60/54.6 r

[51-] Int. Cl ..Fl5b 7/06,Fl6j 15/56 [58] Field of Search ..92/l68;60/546 P; 277/208, 277/70, 75, 79, 25

[56] I References Cited UNITED STATES PATENTS 3,559,406 2/1971 Gardner..60/54.6 P 3,564,849 2/1971 Huruta et ...60/54.6 P 2,988,148 6/1961Conrad et a1. ..277/70 2,997,027 8/1961 lngres 60/54.6 P 3,017,8661/1962 Stelzer... ...60/54.6 P 3,026,852 3/1962 Stelzer ..60/54.6 P

Primary Examiner-William F. ODea Assistant Examiner-Robert J. SmithAttorney-Pierce, Scheffler & Parker [57] ABSTRACT A sealing member forpreventing liquid entrance into the master cylinder housing from theclearance of the connecting portion between the master cylinder housingand the brake booster housing, said sealing member being formed in atubular shape and fitted on a sleeve of the master cylinder housing,comprising an axial projection normally making contact with the boosterhousing, and an air compensating slot.

4 Clairns, 3 Drawing Figures Patented July 25, 1972 2 Sheets-Sheet lPatented July 25, 1972 3,678,687

2 Sheets-Sheet 2 FIG.3 22 18 PRIOR ART 2;; N

/1 0a, omb

SEALING MEANS BETWEEN MASTER CYLINDER AND BRAKE BOOSTER This inventionrelates to sealing means between two members, and more particularly tosealing means between the master cylinder and the brake booster for useon an automotive vehicle.

An object of the invention is to provide a sealing member which canprevent liquid entrance through a clearance of the connecting portionbetween the master cylinder and the brake booster, said liquid beingadmitted from the radiator-grille or the engine room which houses themaster cylinder and the brake booster.

Another object of the invention is to provide a sealing means which issimple in construction and economical in manufacture.

These and other objects and advantages of the invention will becomeapparent from the following description together with the drawings, inwhich:

FIG. 1 is an elevational view partly in section of the master cylinderand brake booster in their installation incorporating a sealing means inaccordance with this invention;

FIG. 2 is an enlarged view of the connecting portion encircled in FIG.1; and

FIG. 3 is a view similar to FIG. 2, but showing a conventionalconnecting portion.

Referring at first to FIG. 3, there is illustrated a conventionalconnection between the master cylinder and brake booster in which thenumeral denotes a master cylinder housing sealingly and slidinglyfitting a hydraulic piston 11 therein. The master cylinder housing 10comprises a radial flange 10a and an axial sleeve 10b. The right handend of the piston 11 is formed with a deep axial recess 12 the apex ofwhich is kept in pressure contact with the inner end of a push rod 13,said push rod being mechanically connected with a conventional brakebooster 14 through an opening 15 of a booster housing 16 and an annularsealing member 17 fixed to the booster housing, said sealing memberbeing provided for prevention of water leakage to the booster 14. Aspacer 18 is provided between the master cylinder housing 10 and thebooster housing 16 for rigid connection therebetween. The mastercylinder housing 10 is fixed to the spacer 18 by first screw bolts 20,while the booster housing 16 is fixed thereto by second screw bolts 19.

The water entering from the engine room or radiator-grille (not shown)will be admitted to a central depression or chamber 21 of the boosterhousing 16 through a gap 22 between the master cylinder housing 10 andspacer 18 or a gap 23 between the booster housing 16 and spacer 18. Thewater having entered the depression 21 will be admitted into the mastercylinder housing, resulting in generation of rust on the slidingsurfaces between the master cylinder housing 10 and hydraulic piston 11.Thus the sliding movement of the hydraulic piston 11 becomes irregular.

ln H08. 1 and 2, sealing means between the master cylinder housing andbooster housing is shown in which the same structure as in theconventional form is designated with primes affixed thereto.

A master cylinder housing 10 is fixed to a booster housing 16' by setscrews 19. A push rod 13' of a conventional brake booster 14' isoperatively connected to a hydraulic piston (not shown) slidably fittedwithin the master cylinder housing 10' through an opening 15' of thebooster housing, a sealing member 17' and a chamber 21'. Around a sleeve10b of the master cylinder housing 10', there is securely fitted atubular seal 24 comprising shoulders 24a and 2412 at each end thereofwhich will form a groove 24c therebetween. There is provided a radialgap 25 between the booster housing 16' and the tubular sealing member24. The tubular member 24 further comprises an axial projection 24dadapted to normally make contact with the annular sealing member 17. Onthe shoulder 24b is provided a radial slot 26 for pneumaticcommunication between the gap 25 and the chamber 21', said slot beingpositioned in the upper part upon assembly. Because of the provision ofsaid air communicatin slot 26, generation of vacuum in the chamber 21causing eformation of the annular seal 17' is prevented, upon actuationof the booster mechanism 14' which will cause the push rod 13' to movetowards left of FIG. 1 in the conventional boosting way.

In case the water enters the radial gap 25 through a clearance 23between the flange 10a of master cylinder housing and the boosterhousing 16', admission of said water to the chamber 21', i.e., to theslide surfaces between the hydraulic piston and the master cylinderhousing will be prevented by virtue of the tubular sealing member 24.The water will pass to the outside through a hollow 27 provided on thebooster housing 16'. 1t will be seen that the provision of the groove24c readily permits the water to pass to the outside.

According to the features of the invention, liquid invasion into themaster cylinder housing may be prevented, whereby the brake booster ormaster cylinder may correctly perform its function. In addition, it isunnecessary to change the form and size of master cylinder or brakebooster, and it is only necessary to provide the sealing means which issimple in form and economical in manufacture.

What is claimed is:

1. In a hydraulic braking system, the combination comprising, a masterbrake cylinder and piston mounted therein, a brake booster, meansincluding a joint for securing said cylinder and said booster togetherand which establishes a chamber therebetween into which a sleeved end ofsaid cylinder extends, said joint permitting air leakage fromthesurrounding atmosphere into said chamber, said booster being providedwith a push rod extending through said chamber and into said sleeved endof said cylinder for actuating the piston of said brake cylinder, atubular sealing member mounted on said sleeved end of said cylinder andextending therebeyond, the ends of said tubular sealing member abuttingsaid brake cylinder and said booster in sealing relationship, the wallof the extended portion of said sealing member having an air ventpassage therethrough to permit air to pass from said chamber into thesleeved end of said cylinder to equalize pressure therein when saidpiston is actuate d.

2. A hydraulic brake system as claimed in claim 1 wherein said sealingmember is provided at the outer end thereof with an annular axialprojection for sealingly engaging said brake booster.

3. A hydraulic brake system as claimed in claim 1 wherein the ends ofsaid tubular sealing member are provided with enlarged shoulder portionswhich define: and limit a peripheral portion having an outer diameterless than the shoulder portions.

4. A hydraulic brake system as claimed in claim 1 wherein said chamberis provided with an outlet at the bottom thereof for any water that mayaccumulate within said chamber.

1. In a hydraulic braking system, the combination comprising, a masterbrake cylinder and piston mounted therein, a brake booster, meansincluding a joint for securing said cylinder and said booster togetherand which establishes a chamber therebetween into which a sleeved end ofsaid cylinder extends, said joint permitting air leakage from thesurrounding atmosphere into said chamber, said booster being providedwith a push rod extending through said chamber and into said sleeved endof said cylinder for actuating the piston of said brake cylinder, atubular sealing member mounted on said sleeved end of said cylinder andextending therebeyond, the ends of said tubular sealing member abuttingsaid brake cylinder and said booster in sealing relationship, the wallof the extended portion of said sealing member having an air ventpassage therethrough to permit air to pass from said chamber into thesleeved end of said cylinder to equalize pressure therein when saidpiston is actuated.
 2. A hydraulic brake system as claimed in claim 1wherein said sealing member is provided at the outer end thereof with anannular axial projection for sealingly engaging said brake booster.
 3. Ahydraulic brake system as claimed in claim 1 wherein the ends of saidtubular sealing member are provided with enlarged shoulder portionswhich define and limit a peripheral portion having an outer diameterless than the shoulder portions.
 4. A hydraulic brake system as claimedin claim 1 wherein said chamber is provided with an outlEt at the bottomthereof for any water that may accumulate within said chamber.